Everyone points to the Wright Brothers as the inventors of human flight. But centuries earlier, it was Leonardo da Vinci who imagined human flight, recognizing how birds used concepts like lift and wing shape to glide high above us.
Now scientists have uncovered new details about the man you might call "the da Vinci" of modern brain science. He was a physiologist named Angelo Mosso who lived in Italy during the 19th century, and until several years ago his manuscripts were mostly collecting dust in the archives of an Italian university.
Inside the manuscripts, researchers found sketches of a contraption built in 1882: the first machine designed to watch the brain at work. It didn't resemble modern brain scanners in any sense.
"It looks like some kind of medieval torture device. I mean it's got a big strap to kind of stop the person moving around too much," says David Field, a psychologist at the University of Reading and an expert on Mosso's machine, called the "human circulation balance." He even built a modern re-creation of it.
Mosso's human circulation balance operated on a simple idea, relatively untested at the time: The brain needs more blood when it works harder.
Mosso would have volunteers lie down on a long wooden plank, carefully balanced on a fulcrum, like a seesaw. He calibrated for anything that might throw off the balance, like the rise and fall of the volunteer's breathing. Then with everything secured, he'd ring a bell.
Mosso reasoned his volunteer's brain would have to process the sound, requiring more blood, making it weigh more, which would tip the scale toward the head's side. According to his manuscripts, that's exactly what happened.
"It sounds like a romantic story, like a dream came true: trying to weight the thoughts," says Stefano Sandrone, a neuroscientist at King's College London. Sandrone is the lead scientist who uncovered Mosso's manuscripts.
Sandrone says Mosso's documents claim his machine could also detect the differing weights of various mental activities. Reading a philosophy book reportedly tipped the balance more than reading something light, like a newspaper.
It remains unclear, though, exactly how well the human circulation balance worked. But, Sandrone says, like Leonardo da Vinci, Mosso had hit upon the right idea: Thinking and blood flow are intimately connected, a fundamental concept behind many of today's brain scanning tools.
However, the human circulation balance had a flip side: The public began to put too much faith in it. In December 1908, a French newspaper reported that people believed the balance "would soon fully explain the physiology of the human brain" and treat mental illnesses.
In this way, Mosso's invention shares some similarities with modern brain scanners, especially the brain scanning technology Mosso's balance directly influenced, known as fMRI (functional magnetic resonance imaging); fMRI reveals what parts of the brain are working harder by tracking how local blood flow changes.
Russ Poldrack, a psychologist at the University of Texas at Austin and an expert on brain scanning technology, says fMRI is an incredibly powerful tool. But he also points to its misuses — in particular, by a branding consultant writing in the New York Times in 2011.
"He had put people in a scanner and shown them iPhones, and claimed that he saw activity in an area of their brain that demonstrated that people were in love with their iPhones," Poldrack says.
The trouble is, that part of the brain is also associated with pain, disgust and a host of other emotions.
The brain is not that simple. But Poldrack has a guess as to why brain technology has often made it seem like it is.
"We're sort of fascinated by seeing thought, which seems so nonmaterial — seeing it as a material thing," he says. "I think people often feel like if they see it on an imaging scan, it's real in a way that it isn't real if it's just being talked about."
In the end, he says, the balance and fMRI are both machines, built by humans, imbued with limitations.
LINDA WERTHEIMER, HOST:
Everyone points to the Wright brothers as the inventors of human flight. But centuries earlier, it was Leonardo da Vinci who imagined human flight. He recognized how birds use lift and wing shape to glide and sketched out how humans might do that too.
Well, today, we have the story of someone you could call the da Vinci of modern brain science. NPR's Chris Benderev tells us more about him.
CHRIS BENDEREV, BYLINE: The da Vinci of brain science was, appropriately enough, also Italian. His name was Angelo Mosso. He lived in the 1800s. And until seven years ago, his manuscripts were collecting a hefty layer of dust in the archives of an Italian University. Then someone opened them up and found sketches from 1882 of the first ever machine designed to watch the brain at work. It didn't look anything like a modern brain scanner.
DAVID FIELD: Looks like some kind of medieval torture device. (Laughing) I mean it's got a big strap - just kind of stopped the person moving around too much.
BENDEREV: This is David Field. He's a psychologist at the University of Reading. He's looked closely at those sketches of Angelo Mosso's machine which was called the human circulation balance. The whole thing was based on a simple idea. Your brain needs more blood when it works harder.
FIELD: He reasoned that he ought to be able to measure any net change in the volume of blood in the brain using what is essentially a lever.
BENDEREV: Here's what Mosso did. He invited people to lie down this long wooden plank which he'd carefully balanced on a fulcrum, kind of like a seesaw. Then he calibrated for anything that might throw off the balance, like the rise and fall of that person's breathing. Finally, with everything set, he'd ring a bell. Mosso figured his volunteer's brain would have to process that sound, requiring more blood, making it weigh more, which would tip the scale towards the head side. And, at least according to his manuscripts, that's exactly what happened. Stefano Sandrone, a neuroscientist at King's College London, is the man who uncovered those manuscripts, and he may just be the world's biggest Angelo Mosso fan.
STEFANO SANDRONE: It's like a romantic story, like a dream came true trying to weigh the thoughts.
BENDEREV: Mosso was trying to weigh thoughts, and Sandrone says, Mosso also figured the bigger the thought, the more it would weigh. So he'd have his volunteer read something light, like a newspaper. And Sandrone says, the balance would tilt a little bit.
SANDRONE: And then the more difficult the task became, such as reading a mathematical book or reading a philosophy book, the more the balance tilted toward the head side.
BENDEREV: That's what Mosso's documents claim. It's not exactly clear how well the balance worked. But Sandrone says, like da Vinci, Mosso had hit upon the right idea.
SANDRONE: Because it's the first proof that there is a relationship between our cognitive activities and our brain blood flow.
BENDEREV: But Russ Poldrack of UT Austin says pretty soon people starting putting too much faith in the human circulation balance.
RUSS POLDRACK: Claims were being made at the point about how, you know, this balance was going to help us understand everything we need to know about the brain.
BENDEREV: Poldrack is an expert on modern-day brain scanning technology. He says at the turn of the last century, people had unrealistic expectations for Mosso's invention, just like they sometimes have for today's brain scanners. Take, for instance, functional magnetic resonance imaging - fMRI - it's basically Mosso's dream come true.
It tells us what parts of the brain are working harder by tracking where the blood goes. And Poldrack says, to be sure, fMRI is an incredible tool. But consider how it was misused a few years back by a branding consultant.
POLDRACK: He had put people in the scanner and shown them iPhones and claimed that he saw activity in an area of their brain that demonstrated that people were in love with their iPhones.
BENDEREV: The problem - that part of the brain is also associated with pain and disgust and other emotions. The brain, it turns out, is just not that simple. But Poldrack has a guess as to why brain technology has often made it seem simple.
POLDRACK: We're sort of fascinated by seeing thought which seems so nonmaterial - seeing it as a material thing. And I think people often feel like if they see it on an imaging scan, it's real in a way that it isn't real if it's just being talked about.
BENDEREV: In the end, says Poldrack, Mosso's balance, the fMRI - they're both machines with limitations. Chris Benderev, NPR News. Transcript provided by NPR, Copyright NPR.